Don Savage
Headquarters, Washington, DC
March 10, 1995
(Phone: 202/358-1547)
Diane Farrar
Ames Research Center, Mountain View, CA
(Phone: 415/604-9000)
RELEASE: 95-24
U.S. INSTRUMENTS TO FLY ABOARD JAPANESE ASTRONOMY MISSION
Several NASA-built components of the Infrared Telescope
in Space (IRTS), the first Japanese orbiting telescope
dedicated to infrared astronomy, will be launched aboard
Japan's Space Flyer Unit (SFU) on March 15 from Japan.
The SFU platform will be launched into low-Earth orbit
from the Tanegashima Space Center in Japan aboard NASDA's H-
II rocket and retrieved by the Space Shuttle later this year.
After several days of systems checks, SFU will be boosted by
onboard rockets to a 500 km (311 mile) circular orbit.
The SFU was developed jointly by Japan's Institute of
Space and Astronautical Science (ISAS), the National Space
Development Agency (NASDA) of Japan, and Japan's Ministry of
International Trade and Industry (MITI).
The IRTS will survey about ten percent of the celestial
sky during its three-week mission. Its lifetime is limited
by the amount of onboard refrigerant necessary to cool the
telescope. During operations, IRTS will be cooled to a
temperature of -455 degrees Fahrenheit to provide high-
sensitivity observations of thermal infrared radiation. Once
the liquid helium coolant is depleted, IRTS will stop
operating and other experiments aboard SFU will be conducted.
IRTS consists of a 15-cm diameter telescope and four
scientific instruments designed and built to study infrared
radiation at wavelengths between approximately 1-1000 microns
(one-millionth of a meter). The orbiting observatory will
provide measurements of the interstellar matter -- the dust
and gas -- in the disk of our galaxy and the interplanetary
dust within our solar system. It also will yield new
information about cool stars and cosmology, the study of the
large-scale structure and evolution of the Universe.
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U.S. scientists, in collaboration with Japanese
colleagues, built two of the four IRTS instruments. Dr.
Thomas Roellig, an astrophysicist at the NASA Ames Research
Center, Moffett Field, CA, is co-Principal Investigator for
the Mid-Infrared Spectrometer (MIRS). The MIRS instrument,
developed in collaboration with Dr. Takashi Onaka of the
University of Tokyo, will provide spectroscopic measurements
at wavelengths between about 5 and 12 microns -- radiation
that is about ten times longer than visible light. MIRS will
study molecular gas in the Milky Way and infrared emission
from the dust within our solar system.
Historically, many astronomical discoveries have been
made when instrument sensitivities were increased by a factor
of ten or more. The two-pound MIRS instrument will provide
measurements that are "100-1000 times more sensitive than
anything that has been measured in this wavelength before,"
said Roellig. "I expect that the most exciting discoveries
will be unexpected ones," he said.
Dr. Andrew Lange, now at the California Institute of
Technology, built the Far-Infrared Photometer (FIRP)
instrument while at the University of California, Berkeley.
Built in collaboration with colleagues at Nagoya University,
FIRP will perform imaging at four far-infrared and
submillimeter bands between 150 and 700 microns. FIRP will
study interstellar dust, variations in cosmic background
radiation, and extragalactic submillimeter radiation. FIRP
will provide important new information about cosmology and
will follow-up earlier discoveries made by the IRAS and COBE
satellites.
Ground tracking support for the IRTS mission will be
provided by the Kagoshima Space Center, Japan, and NASA's
Deep Space Network, with its antennas at Goldstone
(California), Canberra (Australia), and Madrid (Spain).
Science operations will be conducted at Sagamihara Operations
Center, Japan.
After IRTS investigators process and calibrate the
science data, it will be made available to the general
astronomical communities in Japan and the U.S. The Jet
Propulsion Laboratory, Pasadena, CA, will serve as the U.S.
archive site for the data. Funding for the two U.S.
instruments was provided by the Astrophysics Division, NASA
Headquarters, Washington, DC.
The SFU is scheduled to be captured in-orbit by the
Shuttle Endeavour during mission STS-72, scheduled for
December 1995, whose crew is expected to include a Japanese
mission specialist astronaut, Koichi Wakata.
-end-
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